In a production line of a photosensitive film, a magnetic tape, or the like, a broad raw material web such as paper or film is subjected to various kinds of treatment including coating treatment and drying treatment using a photosensitive material and a magnetic material, and then the raw material web is wound in a roll shape (raw material web coil). The raw material web coil is set to a web cutting device. In the web cutting device, first of all, the raw material web drawn from the raw material web coil is cut into a plurality of narrow webs by a slitter. Next, the plurality of narrow webs thus cut are simultaneously wound in a roll shape by a web winding device disposed in a downstream side from the slitter in a web transporting direction, thus a product web coil is obtained.
Two winding shafts are generally disposed in the web winding device. The plurality of narrow webs cut by the slitter are simultaneously wound around after being allocated alternately to each other of the two winding shafts such that the side ends of the narrow webs are not overlapped with each other during winding of the webs. A plurality of winding cores for winding the respective narrow webs and a plurality of approximately cylindrical spacers are mounted to each of the winding shafts so as to be arranged in a line alternately. The spacer defines a position of each of the winding cores such that each winding core corresponds to a position of each allocated narrow web (see Patent Document 1).
Upon finishing the winding of the narrow web, the winding core around which the narrow web is wound is removed from the winding shaft, and a new winding core is set to the winding shaft. Accordingly, in general, the winding cores and the spacers are detachably attached to the winding shaft so as to be removed easily from the winding shaft. Therefore, a stopper for regulating the moving of the winding cores and the spacers in the axial direction is provided at one end of the winding shaft, and the winding cores and the spacers are biased toward the stopper by a predetermined biasing force. Thereby, the spacers abut on both side surfaces of each winding core, and the position of the winding core in the axial direction is defined. Further, chuck claws or the like to be in pressure contact with an inner peripheral surface of the winding core are disposed at the winding shaft. When both winding shafts are rotated, the chuck claw and the inner peripheral surface of the winding core are in sliding contact with each other, and rotational force of the winding shafts is transmitted to the winding core. When the narrow web is wound, the winding core is rotated at a peripheral velocity corresponding to the transporting speed of the web. Therefore, when the winding shaft is rotated faster than the winding core, there occurs sliding between the winding shaft and the winding core due to the rotational difference, and then winding tension in accordance with the sliding coefficient of friction thereof is generated (see Patent Documents 2 and 3).    Reference 1: Japanese Patent Laid-open Publication Number 8-104452 (P.2, FIG. 3)    Reference 2: Japanese Patent Laid-open Publication Number 2000-318889 (P.2 to 3, FIG. 1)    Reference 3: Japanese Patent Laid-open Publication Number 2000-16642 (P.2 to 3, FIG. 1)